Research And Implementation Of Three Phase Current Source Rectifier Based On SiC Power Device

With the large number of applications of power electronics devices, harmonic pollution and reactive loss of the power system is more and more serious. PWM rectifier, as one of power factor correction, has controlled power factor and low harmonic grid current. According to output characteristics, voltage source rectifier and current source rectifier are two main types of PWM rectifier, and current source rectifier developed later than voltage source rectifier. But nowadays with the development of device, modulation and control, current source rectifier is widely used in motor drive, SMES, data center, which is becoming a hotspot in electronics.Firstly, analysis of current source rectifier operation principle and it’s mathematical model are presented.The control method of current source rectifier is also presented in this paper, which provide the foundation for the later analysis of it.Secondly, the overlap time is researched in this paper. The effect of overlap time to current commutation is analyzed and the overlap time result in some part of the zero-voltage turning-on and zero-current turning-off. Then, waveforms of AC side current before and after added overlap time are achieved from analysis of the current commutation process. The expression of overlap current is given according to the pulse equivalent principle and the quantitative relationship between the extra harmonic of AC side current and overlap time is also given on the basis of the Fourier analysis.In addition, a method of restraining the overlap current is proposed. Finally, simulation and experimental results demonstrate the effectiveness of the proposed analysis and restraining method.Finally, a 3kW current source rectifier based on silicon carbide MOSFET is designed and completed. The voltage, current waveforms of open-loop and closed-loop are presented to prove the correctness of it.At the same time, the efficiency constrast and THD of grid current constrast curves of current souce rectifier based on SiC MOSFET and Si IGBT is presented, which demonstrates the silicon carbide devices have advantage in efficiency with high frenquency compared to silicon devices.